EVs isolated from mouse plasma suppress monocytic cell activation and EC-EVs suppress peritoneal leukocyte activation in vivo. (A) Nanoparticle analysis of EVs isolated from mouse plasma by ExoQuick isolation. A representative experiment of 4 is shown. The mode particle size is 112 ± 5.5 nm. (B) EVs isolated from mouse plasma suppress THP-1 monocytic-cell activation in response to LPS treatment. n = 9. (C) Peritonitis was established by IP injection of thioglycollate for 3 days. PBS or HUVEC-derived EC-EVs (60 μg) were injected into the peritoneum and the response to LPS treatment (IP, 2 hours) was assessed in peritoneal leukocytes the following day by qRT-PCR analysis. (D) The levels of proinflammatory genes (Tnf-α, IL-1β, and iNOS) are suppressed by EC-EV injection, whereas immunomodulatory genes are elevated. n = 7.